Use of Different Non Protein Nitrogen Sources in Ruminant Nutrition: A review

摘要

Review was carried out on the use of different nitrogen sources in ruminant nutrition. Non-protein nitrogen (or NPN) is a term used in animal nutrition to refer collectively to components such as urea biuret uric acid and a number of other ammonia compounds which are not proteins but can be converted into proteins by microbes in the ruminant stomach. Urea is a simple compound that contains 46.7 percent of nitrogen compared to 16 percent for most proteins. There is no question but that urea and other non protein nitrogen substances can be fed safely to ruminants to replace part of the dietary protein. When urea with feed sources enters the rumen, it is rapidly dissolved and hydrolyzed into ammonia by bacterial urease. The amount of urea included in concentrate mixtures for cattle or sheep should not exceed 3 percent and usually the addition of 1 to 1.5 percent will prove adequate. In the total ration, the amount of urea should not exceed 1 percent. At these levels of intake, urea has proved an effective for growing and fattening beef cattle and for dairy cattle Urea may cause toxicity and even death in ruminants if it is fed inadequately mixed with other feeds or in too large a dose. The toxic signs can easily be recognized. The slow-release of nitrogen from biuret is better matched to the energy in the diets of cattle consuming low-quality forages, thus improving the utilization of forage and reducing the metabolic cost of eliminating excess nitrogen in urea-based diets. Dried poultry waste (DPW) contains an contains true protein and high amount of NPN in the form of rumen degradable uric acid. Uric acid can be utilized by rumen microbes for protein production. Poultry manure can safely be supplemented to ruminant animals for considerable increase in performance.